Moored mine



Oct. 17, 1961 D. T. WIELAND, JR

MOORED MINE 2 Sheets-Sheet 1 Filed Dec. 4, 1958 INVENTOR.

DANIEL T. W|ELAND,JR.

Oct. 17, 1961 D. T. WIELAND, JR 3,004,488

MOORED MINE Filed Dec. 4, 1958 2 Sheets-Sheet 2 FIG.2.

SENSITROL RELAY STERILIZER BATTERY INVENTOR.

DANIEL T. W|ELAND,JR.

3,004,488 MOORED Daniel T. Wieland, Jr., 1216 Jarrett Road, Norfolk 2,Va. Filed Dec. 4, 1958, Ser. No. 778,265 2 Claims. (Cl. 102--13)(Granted under Title 35, US. Code (1952), see. 266) The inventiondescribed herein may be manufactured and used by or for the Governmentof the United States of America for governmental purposes without thepayment of any royalties thereon or therefor.

This invention relates to a contact mine having an improved anti-sweepdevice for use in and around friendly harbors. More specifically, thisinvention provides a mine arming system whereby the mine is maintainedin the passive condition until an attempt is made to sweep it.

Prior to this invention, devices employed to protect a moored mineagainst sweeping were designed to damage the sweep gear. While suchdevices prolong the time re quired to sweep an area they are not veryeffective in destroying or damaging desirable targets because all themoored mines are eventually swept and the enemy is not mislead intothinking a mined harbor has been swept.

In the present invention the mine is secured to the anchor so that itsinks with the anchor and rests upon the harbor floor. Theelectromagnetic field set up by an impulse of strong current applied tothe sweep wire of a mine sweeper moving through the water releases themine and allows it to float up to a selected depth where it is inposition to sink or damage any ships passing over the supposedly sweptarea.

One object of the present invention is to provide a moored contact minewhich operates against a magnetic sweeper.

Another object is the provision of a contact mine ineluding a magneticsearch coil which moors the mine in the shipping lanes only after anattempt has been made to magnetically sweep the mine.

A further object is to provide a contact mine for use in a friendlyharbor which normally lies on the harbor floor to permit free passage ofshipping in the harbor but is moored when an attempt is made tomagnetically sweep the harbor by an enemy.

These and many other objects, and advantages of this invention willbecome apparent when the following specification is read and consideredin conjunction with the accompanying drawings wherein like numeralsdesignate like or similar parts throughout the drawings in which:

FIG. 1 indicates the sequence of operation of the mine;

FIG. 2 is a perspective view of the mine before release of the minecasing from the mine anchor; and

FIG. 3 is a sectional view of the mine mooring mechamsm.

Referring now with greater particularity to the drawings, the mine,comprising a mine casing 11 supported upon a mine anchor 12 by aplurality of brackets 13 fixed to anchor 12, is launched into a body ofwater 14 and commences to sink to the floor 16 thereof.

Although mine casing '11 is positively buoyant it does not separate fromthe anchor 12 because it is secured by a rod or piece of stout cable 17connected between lugs and 20 on the casing and the anchor respectively.A mooring cable bail 21 is fixed to the mine between two eyes 18 and isconnected to one end of mooring cable 22. The other end of cable 22 issecured to a freely rotatable drum (not shown) within the mine anchor.After launching, the mine sinks to the floor of the harbor so that itdoes not present a hazard to friendly ships in the harbor.

Attached to the mine anchor is a housing 36 and a coarse search coil 23.In the event that the harbor is taken over by an enemy, and an attemptis made to sweep the harbor, search coil 23 actuates a sensitrol relay24 encased in a foam rubber cushion 19 and disposed within the coil formto complete the circuit across the igniter wire 26 disposed within acontainer 27 fixed by bracket 28 to the mine anchor 12. Container 27 hasa C shaped'portion 29 at one end to receive the cable 17. Uponcompletion of the igniter wire circuit current from a battery 31 inhousing 36 flows through igniter 26 to initiate a detonator 32 which inturn ignites booster 33 to detonate the shaped charge 34 therebysevering cable :17. The mine case 11, thus freed, floats upward and ismoved just below the surface so that it is detonated when a shipcontacts one of the horns 39. This may be accomplished by hydrostatbight releasing means or since the depth of the harbor is known, byemploying a mooring cable cut to the desired length.

Search coil 23 must be rather coarse and insensitive since it should beactuated only when the mine is attempted to be swept by the strongmagnetic impulses generated by a magnetic sweep wire.

A sterilizer 37 may be inserted in the firing circuit to disarm the mineafter a selected period of time. A delay circuit 38 preferably isincluded in the firing circuit to allow a time lag between the sweep andtime the mine is moored so that the mine will not sink the mine sweeperbut will destroy the more desirable targets that follow it.

While the invention has been described with reference to one specificexample, it will be understood by those skilled in the art, afterunderstanding this invention, that it is susceptible of many alterationsand modifications without departing from the spirit and scope of theinven tion. Accordingly the invention is to be limited only by the scopeof the appended claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A moored contact mine adapted to be sown in a friendly harborcomprising; a mine casing having an explosive charge therein, a mineanchor, frangible means securing said mine casing to said anchor wherebysaid mine casing sinks to the floor of said harbor with said anchor whenthe mine is launched, a slack cable connected between said anchor andsaid casing, a coarse search coil disposed on the mine anchor adapted togenerate an electrical pulse only when it is subject to a strongelectromagnetic field of an enemy magnetic mine sweeper, and meansoperatively connected to said search coil and disposed adjacent to saidfrangible means to fracture said frangible means upon receipt of anelectrical pulse from said coarse coil to release said mine casing andpermit it to float upward a predetermined distance and lie in the pathof travel of ships in the harbor.

2. The contact mine of claim 1 wherein said means operatively connectedto the search coil comprises; a container having an opening disposedabout said frangible means, a shaped explosive charge disposed withinsaid container adjacent said opening and adapted to fracture saidfrangible means upon initiation, and an igniter wire electricallyconnected to said search coil and adapted to detonate said shaped chargeupon receipt of a pulse from the coil.

Johnson Feb. 15, 1955 Turlay Apr. 26, 1955 ratented Oct. 17, 1961

